object: move object containment out of transmogrifier into it's own module

lib/pleroma/object/containment.ex

@@ -0,0 +1,64 @@
+defmodule Pleroma.Object.Containment do
+  @moduledoc """
+  # Object Containment
+
+  This module contains some useful functions for containing objects to specific
+  origins and determining those origins.  They previously lived in the
+  ActivityPub `Transmogrifier` module.
+
+  Object containment is an important step in validating remote objects to prevent
+  spoofing, therefore removal of object containment functions is NOT recommended.
+  """
+
+  require Logger
+
+  def get_actor(%{"actor" => actor}) when is_binary(actor) do
+    actor
+  end
+
+  def get_actor(%{"actor" => actor}) when is_list(actor) do
+    if is_binary(Enum.at(actor, 0)) do
+      Enum.at(actor, 0)
+    else
+      Enum.find(actor, fn %{"type" => type} -> type in ["Person", "Service", "Application"] end)
+      |> Map.get("id")
+    end
+  end
+
+  def get_actor(%{"actor" => %{"id" => id}}) when is_bitstring(id) do
+    id
+  end
+
+  def get_actor(%{"actor" => nil, "attributedTo" => actor}) when not is_nil(actor) do
+    get_actor(%{"actor" => actor})
+  end
+
+  @doc """
+  Checks that an imported AP object's actor matches the domain it came from.
+  """
+  def contain_origin(id, %{"actor" => nil}), do: :error
+
+  def contain_origin(id, %{"actor" => actor} = params) do
+    id_uri = URI.parse(id)
+    actor_uri = URI.parse(get_actor(params))
+
+    if id_uri.host == actor_uri.host do
+      :ok
+    else
+      :error
+    end
+  end
+
+  def contain_origin_from_id(id, %{"id" => nil}), do: :error
+
+  def contain_origin_from_id(id, %{"id" => other_id} = params) do
+    id_uri = URI.parse(id)
+    other_uri = URI.parse(other_id)
+
+    if id_uri.host == other_uri.host do
+      :ok
+    else
+      :error
+    end
+  end
+end

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -1,5 +1,6 @@
 defmodule Pleroma.Web.ActivityPub.ActivityPub do
   alias Pleroma.{Activity, Repo, Object, Upload, User, Notification}
+  alias Pleroma.Object.Containment
   alias Pleroma.Web.ActivityPub.{Transmogrifier, MRF}
   alias Pleroma.Web.WebFinger
   alias Pleroma.Web.Federator
@@ -739,7 +740,7 @@ def fetch_object_from_id(id) do
              "actor" => data["actor"] || data["attributedTo"],
              "object" => data
            },
-           :ok <- Transmogrifier.contain_origin(id, params),
+           :ok <- Containment.contain_origin(id, params),
            {:ok, activity} <- Transmogrifier.handle_incoming(params) do
         {:ok, Object.normalize(activity.data["object"])}
       else
@@ -773,7 +774,7 @@ def fetch_and_contain_remote_object_from_id(id) do
              recv_timeout: 20000
            ),
          {:ok, data} <- Jason.decode(body),
-         :ok <- Transmogrifier.contain_origin_from_id(id, data) do
+         :ok <- Containment.contain_origin_from_id(id, data) do
       {:ok, data}
     else
       e ->

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -4,6 +4,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   """
   alias Pleroma.User
   alias Pleroma.Object
+  alias Pleroma.Object.Containment
   alias Pleroma.Activity
   alias Pleroma.Repo
   alias Pleroma.Web.ActivityPub.ActivityPub
@@ -13,56 +14,6 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
 
   require Logger
 
-  def get_actor(%{"actor" => actor}) when is_binary(actor) do
-    actor
-  end
-
-  def get_actor(%{"actor" => actor}) when is_list(actor) do
-    if is_binary(Enum.at(actor, 0)) do
-      Enum.at(actor, 0)
-    else
-      Enum.find(actor, fn %{"type" => type} -> type in ["Person", "Service", "Application"] end)
-      |> Map.get("id")
-    end
-  end
-
-  def get_actor(%{"actor" => %{"id" => id}}) when is_bitstring(id) do
-    id
-  end
-
-  def get_actor(%{"actor" => nil, "attributedTo" => actor}) when not is_nil(actor) do
-    get_actor(%{"actor" => actor})
-  end
-
-  @doc """
-  Checks that an imported AP object's actor matches the domain it came from.
-  """
-  def contain_origin(id, %{"actor" => nil}), do: :error
-
-  def contain_origin(id, %{"actor" => actor} = params) do
-    id_uri = URI.parse(id)
-    actor_uri = URI.parse(get_actor(params))
-
-    if id_uri.host == actor_uri.host do
-      :ok
-    else
-      :error
-    end
-  end
-
-  def contain_origin_from_id(id, %{"id" => nil}), do: :error
-
-  def contain_origin_from_id(id, %{"id" => other_id} = params) do
-    id_uri = URI.parse(id)
-    other_uri = URI.parse(other_id)
-
-    if id_uri.host == other_uri.host do
-      :ok
-    else
-      :error
-    end
-  end
-
   @doc """
   Modifies an incoming AP object (mastodon format) to our internal format.
   """
@@ -99,7 +50,7 @@ def fix_addressing(map) do
 
   def fix_actor(%{"attributedTo" => actor} = object) do
     object
-    |> Map.put("actor", get_actor(%{"actor" => actor}))
+    |> Map.put("actor", Containment.get_actor(%{"actor" => actor}))
   end
 
   def fix_likes(%{"likes" => likes} = object)
@@ -277,7 +228,7 @@ def handle_incoming(%{"id" => id}) when not (is_binary(id) and length(id) > 8),
   # - emoji
   def handle_incoming(%{"type" => "Create", "object" => %{"type" => objtype} = object} = data)
       when objtype in ["Article", "Note", "Video", "Page"] do
-    actor = get_actor(data)
+    actor = Containment.get_actor(data)
 
     data =
       Map.put(data, "actor", actor)
@@ -360,7 +311,7 @@ defp get_follow_activity(follow_object, followed) do
   def handle_incoming(
         %{"type" => "Accept", "object" => follow_object, "actor" => actor, "id" => id} = data
       ) do
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = followed <- User.get_or_fetch_by_ap_id(actor),
          {:ok, follow_activity} <- get_follow_activity(follow_object, followed),
          {:ok, follow_activity} <- Utils.update_follow_state(follow_activity, "accept"),
@@ -386,7 +337,7 @@ def handle_incoming(
   def handle_incoming(
         %{"type" => "Reject", "object" => follow_object, "actor" => actor, "id" => id} = data
       ) do
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = followed <- User.get_or_fetch_by_ap_id(actor),
          {:ok, follow_activity} <- get_follow_activity(follow_object, followed),
          {:ok, follow_activity} <- Utils.update_follow_state(follow_activity, "reject"),
@@ -410,7 +361,7 @@ def handle_incoming(
   def handle_incoming(
         %{"type" => "Like", "object" => object_id, "actor" => actor, "id" => id} = data
       ) do
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = actor <- User.get_or_fetch_by_ap_id(actor),
          {:ok, object} <- get_obj_helper(object_id) || fetch_obj_helper(object_id),
          {:ok, activity, _object} <- ActivityPub.like(actor, object, id, false) do
@@ -423,7 +374,7 @@ def handle_incoming(
   def handle_incoming(
         %{"type" => "Announce", "object" => object_id, "actor" => actor, "id" => id} = data
       ) do
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = actor <- User.get_or_fetch_by_ap_id(actor),
          {:ok, object} <- get_obj_helper(object_id) || fetch_obj_helper(object_id),
          {:ok, activity, _object} <- ActivityPub.announce(actor, object, id, false) do
@@ -477,10 +428,10 @@ def handle_incoming(
       ) do
     object_id = Utils.get_ap_id(object_id)
 
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = actor <- User.get_or_fetch_by_ap_id(actor),
          {:ok, object} <- get_obj_helper(object_id) || fetch_obj_helper(object_id),
-         :ok <- contain_origin(actor.ap_id, object.data),
+         :ok <- Containment.contain_origin(actor.ap_id, object.data),
          {:ok, activity} <- ActivityPub.delete(object, false) do
       {:ok, activity}
     else
@@ -496,7 +447,7 @@ def handle_incoming(
           "id" => id
         } = data
       ) do
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = actor <- User.get_or_fetch_by_ap_id(actor),
          {:ok, object} <- get_obj_helper(object_id) || fetch_obj_helper(object_id),
          {:ok, activity, _} <- ActivityPub.unannounce(actor, object, id, false) do
@@ -566,7 +517,7 @@ def handle_incoming(
           "id" => id
         } = data
       ) do
-    with actor <- get_actor(data),
+    with actor <- Containment.get_actor(data),
          %User{} = actor <- User.get_or_fetch_by_ap_id(actor),
          {:ok, object} <- get_obj_helper(object_id) || fetch_obj_helper(object_id),
          {:ok, activity, _, _} <- ActivityPub.unlike(actor, object, id, false) do

test/object/containment_test.exs

@@ -0,0 +1,66 @@
+defmodule Pleroma.Object.ContainmentTest do
+  use Pleroma.DataCase
+
+  alias Pleroma.User
+  alias Pleroma.Object.Containment
+  alias Pleroma.Web.ActivityPub.ActivityPub
+
+  import Pleroma.Factory
+
+  describe "general origin containment" do
+    test "contain_origin_from_id() catches obvious spoofing attempts" do
+      data = %{
+        "id" => "http://example.com/~alyssa/activities/1234.json"
+      }
+
+      :error =
+        Containment.contain_origin_from_id(
+          "http://example.org/~alyssa/activities/1234.json",
+          data
+        )
+    end
+
+    test "contain_origin_from_id() allows alternate IDs within the same origin domain" do
+      data = %{
+        "id" => "http://example.com/~alyssa/activities/1234.json"
+      }
+
+      :ok =
+        Containment.contain_origin_from_id(
+          "http://example.com/~alyssa/activities/1234",
+          data
+        )
+    end
+
+    test "contain_origin_from_id() allows matching IDs" do
+      data = %{
+        "id" => "http://example.com/~alyssa/activities/1234.json"
+      }
+
+      :ok =
+        Containment.contain_origin_from_id(
+          "http://example.com/~alyssa/activities/1234.json",
+          data
+        )
+    end
+
+    test "users cannot be collided through fake direction spoofing attempts" do
+      user =
+        insert(:user, %{
+          nickname: "rye@niu.moe",
+          local: false,
+          ap_id: "https://niu.moe/users/rye",
+          follower_address: User.ap_followers(%User{nickname: "rye@niu.moe"})
+        })
+
+      {:error, _} = User.get_or_fetch_by_ap_id("https://n1u.moe/users/rye")
+    end
+
+    test "all objects with fake directions are rejected by the object fetcher" do
+      {:error, _} =
+        ActivityPub.fetch_and_contain_remote_object_from_id(
+          "https://info.pleroma.site/activity4.json"
+        )
+    end
+  end
+end

test/web/activity_pub/transmogrifier_test.exs

@@ -945,61 +945,4 @@ test "it rejects activities which reference objects that have an incorrect attri
       :error = Transmogrifier.handle_incoming(data)
     end
   end
-
-  describe "general origin containment" do
-    test "contain_origin_from_id() catches obvious spoofing attempts" do
-      data = %{
-        "id" => "http://example.com/~alyssa/activities/1234.json"
-      }
-
-      :error =
-        Transmogrifier.contain_origin_from_id(
-          "http://example.org/~alyssa/activities/1234.json",
-          data
-        )
-    end
-
-    test "contain_origin_from_id() allows alternate IDs within the same origin domain" do
-      data = %{
-        "id" => "http://example.com/~alyssa/activities/1234.json"
-      }
-
-      :ok =
-        Transmogrifier.contain_origin_from_id(
-          "http://example.com/~alyssa/activities/1234",
-          data
-        )
-    end
-
-    test "contain_origin_from_id() allows matching IDs" do
-      data = %{
-        "id" => "http://example.com/~alyssa/activities/1234.json"
-      }
-
-      :ok =
-        Transmogrifier.contain_origin_from_id(
-          "http://example.com/~alyssa/activities/1234.json",
-          data
-        )
-    end
-
-    test "users cannot be collided through fake direction spoofing attempts" do
-      user =
-        insert(:user, %{
-          nickname: "rye@niu.moe",
-          local: false,
-          ap_id: "https://niu.moe/users/rye",
-          follower_address: User.ap_followers(%User{nickname: "rye@niu.moe"})
-        })
-
-      {:error, _} = User.get_or_fetch_by_ap_id("https://n1u.moe/users/rye")
-    end
-
-    test "all objects with fake directions are rejected by the object fetcher" do
-      {:error, _} =
-        ActivityPub.fetch_and_contain_remote_object_from_id(
-          "https://info.pleroma.site/activity4.json"
-        )
-    end
-  end
 end